Another note - most likely, IS won't be used at this bit rate, or it will be used in much reduced way than it is in this test - purpose of the demo is to check amount of stereo reduction (if any) and some other artifacts it might introduce.

Few of those are already known and we are working on them

So, at lower bitates (e.g. 48-80 kbps) we might improve listening experience over common LC-AAC implementations even more for those without ability to use HE-AAC

[11.00 - 13.00] The loudest trumpet note is distorted (it sounds like ringing on a very short moment) with IS encoding. The other one is less disturbing.Additional note: the distortion is also audible on the beginning (two first seconds). This time both encodings are concerned, but IS is really more unpleasant to my ears. It's not really ringing, but noise or fat sounding.Additional note No.2: sample sm01 suffers from ringing (more with IS), but I haven't ABXed it yet.

I heard more smearing for IS during the introduction (guitar + ta-ta-ta-ta) but I decided to ABX something which isn't located on the very beginning. I failed :/

This is all for this night. Now, bed. Tomorrow, some other files P.S. The german speech sample sounds really bad, with aggressive whispering I can sometimes heard on TV. Are your encodings transcoded from a lossy source?

So, at lower bitates (e.g. 48-80 kbps) we might improve listening experience over common LC-AAC implementations even more for those without ability to use HE-AAC†

CT supports HE-AAC up to 128 kbit/s. After some abx test ( Winamp 5.12 CT encoder vs Nero 4.9.9.9 for the samples of this topic ) I found that CT encoder can be on par with LC-AAC at 96 kbit/s or even beter on some samples like Waiting and Layla

Indeed there should be a test to determine if statement that SBR is usefull only up to 80 kbit/s is still truely.

Conclusion: all are more or less distinguishable from the original. When it comes to IS vs. no IS, no IS sounds better to my ears. For IS vs. IS2, no idea. I think IS2 was a bit better, but as you can see from the ABX logs, I didn't manage to get an acceptable result.

I also noticed that IS has an artifact during the first few seconds of applause. It produces something like a "Krr".

We will continue to improve IS (some more things are left to be done) - but I also think IS should be used at bit rates lower than 96 kbps - perhaps 80 and definitely 64 kbps.

Interesting is that I definitely found out that IS in AAC is much better than IS in MP3 - because AAC has TNS tool, which should shape the noise to avoid IS articacts of bad noise positioning in the R channel (thus generating failed stereo image)

Glad to hear Nero is doing something new to AAC, I've a question that is the AAC+IS require the IS support from AAC decoder just like SBR and PS does?My new mobile phone seems to only support LC-AAC, so I can't get any benifit from HE-AAC, if LC+IS doesn't require decoder's special support, that could be cool to me.

IS is a part of the original, very first, MPEG 2 LC-AAC spec, so *all* AAC decoders have support for it.

Thanks Garf, glad to hear that. But why IS is already supported by decoders but no encoders support IS till now?(except the coming Nero encoder )And when can we expect to have a public test version of Nero AAC encoder that supports IS? And did you do any internal comparison about LC+IS and HE-AAC at 64/80 Kbps? I'm interested at which one could winOr it is possible to use HE+IS+PS in the future?

IS is a part of the original, very first, MPEG 2 LC-AAC spec, so *all* AAC decoders have support for it.

Thanks Garf, glad to hear that. But why IS is already supported by decoders but no encoders support IS till now?(except the coming Nero encoder )

It appears to be quite tricky to use correctly.

QUOTE

And when can we expect to have a public test version of Nero AAC encoder that supports IS? And did you do any internal comparison about LC+IS and HE-AAC at 64/80 Kbps? I'm interested at which one could winOr it is possible to use HE+IS+PS in the future?

We are still looking into this. For close calls we may do further public tests here.

sure it would need testing... but if the lc-aac part isn't forced down to half the samplerate (22.05khz) then sbr wont have as much bandwidth to cover (instead of the entire top half, maybe just the top fourth) my speculation here is based on plusV fullrate (44.1khz mp3 + 44.1khz plusV)... we shall see how it goes when it gets tested though